Desc : When I add a description in Share.ShareFile action, the Description parameter is not read and so not managed.
Fix : After digging into the Fuse source code, I found why:
In the file Fuse.Share.g.cpp, into the method named ShareModule::ShareFile, at the line 141 here is what is written:
uString* description = (uPtr(args)->Length() > 1) ? (uString*)::g::Uno::String::op_Addition1(::STRINGS[4/*""*/], uPtr(args)->Strong<uObject*>(1)) : ::STRINGS[4/*""*/];
It should be
uString* description = (uPtr(args)->Length() > 1) ? (uString*)::g::Uno::String::op_Addition1(::STRINGS[4/*""*/], uPtr(args)->Strong<uObject*>(2)) : ::STRINGS[4/*""*/];
Because 1 is the mime-type.